Variable Pitch Outlet Guide Vanes for Un-Ducted Turbofan Engine
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Solution Overview
Problem
Certain gas turbine engines lack a mechanism to actuate outlet guide vanes without an outer nacelle, limiting their ability to optimize airflow and noise reduction.
Innovation Solution
A propulsion device with variable pitch guide vanes attached to a housing or core in a rotatable manner, equipped with a pitch change mechanism to adjust the vane pitch, allowing for efficient airflow direction without the need for an outer nacelle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If outlet guide vanes are attached to an outer nacelle for rotation, then the vanes can be actuated to optimize airflow and reduce noise, but the engine structure becomes more complex and requires additional components
Solution Approach 1:
The patent extracts the guide vane rotation mechanism from the traditional outer nacelle structure and relocates it to the inner core assembly. The guide vanes are now attached to the core assembly at radially inner ends, eliminating the need for an outer nacelle while preserving the ability to rotate and actuate the vanes for noise reduction and airflow optimization
Solution Approach 2:
The guide vane rotation mechanism is nested within the existing core assembly structure. The vanes are attached to the core assembly at radially inner ends, with the rotation mechanism integrated into the core assembly itself rather than requiring a separate outer nacelle, creating a compact nested arrangement
2Adaptability or versatility
If an outer nacelle is used to enclose fan blades and guide vanes, then the guide vanes can be rotated at radially outer ends, but the engine design becomes more complex and less adaptable
Solution Approach 1:
The patent removes the outer nacelle from the design and extracts the guide vane attachment from radially outer ends to radially inner ends of the core assembly. This extraction eliminates the need for the enclosing nacelle structure while maintaining the functional capability to rotate and actuate the guide vanes, thereby increasing design flexibility and adaptability
Data Source
AI summary
An un-ducted turbofan engine defining a radial direction and an axial direction that includes a core engine, a fan, a plurality of variable outlet guide vanes, and a pitch change mechanism. Each of the plurality of variable outlet guide vanes are attached in a rotatable manner to the core engine of the un-ducted turbofan engine. The pitch change mechanism is positioned radially between the engine air flowpath and the plurality of variable outlet guide vanes and coupled to at least one variable outlet guide vane of the plurality of variable outlet guide vanes for changing a pitch of the at least one variable outlet guide vane.